Piston



De. 2, 1930. s. J. MANs`F|ELb PISTON Filed Dec AfA/2,

`. INVENTOR..

- ATTfRNEY.

` 95, but also teac Patented Dec. 2, 1930 1 PA'PENT;A OFFICE SAMUL J. MANSFIELD, OF DALLAS, TEXAS PISTON Application led December 13, 1928. Serial No. 325,819. A

Vrlhis invention relates to pistons for internal combustion engines and it has particular reference to thatvtypeof piston havin` a head and a guide composed of metals havlng 5 different characteristics', each performing its peculiar function in bringing about uniformity of operation and the principal object of the 'inventionresides in the improved manufacture of a4 piston2 possessing the prerequi- 103` site of expansionand contraction in accordance with the changes of motor temperature, yethaving the characteristics of a single piece piston. I :d Another andn important object of the in- 15 vention resides in the provisionl of an improved lubricating system by which the piston may be properly lubricated in operation, and by reason of which the annoyance of pumping oil, so common to the ordinary piston. will be eliminated.

Another object of the invention resides in 'the peculiar construction of the improved pisf ton, through the medium of which, not only are the foregping and other objects attained, ing the economical construction of a piston comprised -of different metals having a co-efcientrof, expansion combined with its lubricating system, `which metes out the proper amount of lubricating medium,

' "'30 yet providing `for instantaneous lubrication for the walls of the cylinder after they have -been drained overa period in which the pistons have been motionless therein.

With the foregoing objects as paramount,

the invention resides further in the salient features of construction' and arrangement of arts, hereinafter morev specifically descri ed and shown /inthe accompanying drawings, wherein Figure 1 represents 'a side elevationalviewl of a piston constructed according to the presen t invention, v

Figure 2 is an axial sectional view thereof.

y Figure 3 is a sectional vievl on lines 3-3 of Figure 1 and v Figure 4' is a detail view in perspective of one of the sections formingthe guide for the Continuing now more in detail with the` changes, has been long sought for. And' in 55 this connection it may be mentioned that such a piston must be composed of metals having a decidedly different reaction toheat and cold. The problem has been to combineA these metals in such manner that the effect of expansion andcontraction of one element under severe temperature changes would not be such as to cause injury to the other. Moreover, it is desirable that the metal of which the guide or-skirt of the piston is comprised be 55 of slow Wearing qualities, yet being capable of adjusting itself to the walls of the cylinder, which have becomeworn to such an extent as to be untrue and to the expansion and contraction of the head, which is the part of the piston undergoing the most severe strain.

In so adjusting itself to the wallsof the cylinder, the objectionable slapping which occurs when the cylinder becomes out-of:

roundrthrough the use of the ordinary piston, 75.

tive reaction to sudden temperature changes 30 without ill effect; a thorough lubricating sysv tem by which this medium-'is heldin checkto prevent overlubrication, and a i means by which the piston `guide may adjust itself to j the c linder walls to prevent piston slap- 35 ping andundue wear. v i v Accordingly, 1 designates generall tle fh'ead in which ring grooves 2 are provi ed as in the conventional pistons. This head is of cast metal, preferabl castiron, aluminum, or 99 the like and, as wil become manifest later, may be either cast into the guide, tobe presentlgl described,or cast separately and welded to t e guide, v The guide, which is comprised of two semicircular members 3, one of which is illustrated in Figure 4, is aixed tothe head in the manner shown and to be later described more in detail, and has an annular depression 4 about its center, which serves in the capac- 100 ity of an oil reservoir, containing suflicient oil' under operating conditlons to effectively lu bricate the cylinder walls.

It will be particularlj noted that the members 2 are of corresponding size and shape, that is to say, are of such similarity that a single die may be used in making both, which is an important feature in economical manufacture of the piston.

When fitted together in the manner exempliiied in Figure 1, an oblique slit 5 is left on either side of the guide, both above and below the opening 6. A limited, but sufficient amount of expansion and contraction of the ends of the guide is allowed by reason of these slits, therefore, since the portions of the guide opposing the annular depression are the only parts of the piston coming into direct contact with the walls of the cylinder,

the expansion and contraction permitted bythe slits 5 is sufcient to enable the piston to, at all times, adjust itself to the walls of the cylinder, without default in the eiicient performance of the piston. Moreover, due to the oblique disposition of the slits 5, scoring of the walls of the cylinder by exposed, irregular edges is obviated.

With further reference to the opening 6, into which the slits 5 extend, it will be noted that half of this opening is cut from one of the sections 3 while the other half is cut from the companion section. The purpose in making this opening of oblong shape is to provide for ready vertical alignment of the wrist pin bearings 7 cast integral with the head, without requiring tooexacting effort when assembling the piston.

It is intended for the sake of strength and durability, that the elements be welded to gether to completethe piston, and in this connection reference is made to Figure 3. The head 1 is first poured into a mould in which a pattern has been embedded to provide for a series of annularly spaced indentations 7a around the lower edge 8, corresponding with the inwardly extending punched projections 9 about the waist of the guide members 3. It is obvious that when the head and the two guide sections are joined together inthe relationship shown in Figures 1 and 2, these projections will enter the indentations 7a and upon illingvthe indentations with molten metal under an electric or other welding torch the elements are held in posltively fixed relationship having the characteristics of a single piece piston. After having so joined the head and guide sections together, the piston is placed upon a lathe and turned to proper standard size.

It is obvious also that the head and guide sections may be as readily assembled by arranging the guide sections 3 in a form in which an impression of the head l has been made in the sand by a matrix, and pouring the molten metal through a hole in the top of the form. The metal of course, when chilled, will attain the form of the head shown, and the apertures 10 will have been filled by the metal, the latter iiowing around the projections 9 which, after having been embedded in the metal forming the head, provide a positively secure locking means. The composite piston thus formed is then rplaced in a lathe as in the previous oase and finished to the desired size.

In producing a composite piston as last described, that is, in casting the head integral with the guide, there is a likelihood that the metal forming the head will chill before fusing with the metal guide sections and in the absence of means to offset later effects of this condition, the guide sections might give trouble in working loose. In the present invention, the projections 9\ extending inwardly of the walls of the guide sec tions 3 form a most eifective anchor in the manufacture of pistons in this manner to provide the maximum of efficiency in the operation of this particular type of composite piston. v

It is more desirable, however that the head and guide sections be welded together in the manner first described, the method of construction embodying substantially the same principle as in the other case.

Referring now particularly to the oiling system of the improved piston, Figure 2 shows by following the arrows, the course taken by the lubricant during the reciprocative movements of the piston. It is understood that a positive seal is provided 1n the `cylinder by the piston, as hereinbefore stated, and known to those familiar with the art as being the desideratum of eiiiciency,yet the openings 11, and 12, allow passage of the minimum amount of oil to properly lubricate the piston without flooding the rings, which is the annoying disadvantage found to exist in a great number of pistons seeking to provide the desirable feature of flexibility under all operating conditions.

It will be observed that the openings 11 andv12 are of slightly different nature, the former being only a plain hole while the latter provides an overhanging lip 13. The object of this lip is to defiect oil which has been splashed upward into the piston by the crank shaft, and descends along the inner walls of the piston.

As the piston approaches the lowerextremity of the cylinder, the lower edge thereof receives a bath of oil and at the same time, the oil is splashed upward into the hed. The oil is carried upward by the piston as it moves toward the top of the cylinder, as shown by the arrows. exteriorlv of the walls of the guide in Figure 2 and in moving upward, the film of oil remaining on the walls of the cylinder in the preceding stroke is wiped off by the deflected portion ipsa-177 of the guide at a, and takes the course shown by the arrow at this point, into the area between the walls of the head 1 and guide,

`indicated at b, whereupon it drains out of this area, through openings l1 ,spaced annularly about the guide, into what is, under operating conditions,l a reservoir 4, hereinbefore mentioned. The excess oil in this reservoir iinds'an escape through opening l2 at the bottom ofthe reservoir 4, back intg the inner surface of the guide, whereupon it continues as indicated by Vthe arrows, downward into the crank case. 1 l

It is a desirable feature in a piston to provide fr immediate'lubrication. for the iston upon its first -stroke after a perio of idleness, that is, after the film of oil has had sufficient time to drain back into the crank case, leaving the cylinder walls comparatively dry. This feature is provided in the present case by leaving an annular space at a below the openings 11, and above the oint of connection between. the head an guide. Sufficient amount of oil is left lremaining in this reserve to provide a cushion of oil upon which-the piston mayride in its initial movement, or until. it receivesa supply from the crank cas'e.

It is apparent from the foregoing that at no time is it possible for an over supply of oil to pass above the guide to be handled by the oil ring. Under ordinary conditions, this ring, or the ring within the lower groove 2, is required to restrain the oil from passing above the-pistonand if this ring is not entirely effective, at al1 times, the piston will lower part of said spacel and having an anjacent end edges of the sections being free of the head and spaced throughout their lengths to -allow for expansion and contraction.

3. A piston having a head and a sectional guide cast integral withthe head, said guide having anchorin elements between its top and bottom whic are embedded in the head, the adjacent end edges of the sections being inclined and free of the head and Y aced and further having cut-outs which con]0int 1y define an openin disposed between the top and bottom of t e ide.

4. A piston having a dad and a sectional guide cast inte al with he head, said ide having integra anchoring means struc -out therefrom and which are cast into the head, the confronting edges of Nthe sections being spaced and free of connection with the head. In testimony whereof Iuaii m si ature.

SAMUEL J. F Ll).`

act to literally pump the oil into the firing area of the cylinder, whereas, in the present case, only a thin'film is permitted to interpose the piston and cylinder wall, and at no time does it attain such volume as to drown out the oil ringof the piston even under the' most strenuous operating conditions. The reservoir provided in the annular depression 4 is at all times kept replenished b the passage of oil in the manner describe whether lso the motor is operating at a highl rate of speed or idling.

It is obvious from the foregoing that the present invention while being composed of metals having a different reaction to strain or heat, its construction is such as to provide for stress and changes in temperature without affecting itsperformance 1n thecylinder.

Manifestly, the construction shown is capable ofl considerable modification, or such modification as is considered within the sco of the appended claims is considered wit in the spirit of the invention.

I claimv 1. In apiston, a head, a guide secured to the head, there bein an annular space between the upper en of the guide and the head which opens outwardly, said guide having openings which communicate with the 

